package com.hmdp.utils;


import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

/**
 * 用于 生成分布式id  全局唯一id
 */
@Component
public class RedisIdWorker {

    /**开始的时间戳**/
    private static  final Long  BEGIN_TIMESTAMP = 1672531200L;
    private static  final int  COUNT_BITS = 32;
    @Resource
    private StringRedisTemplate stringRedisTemplate;
    public long nextId(String  keyPrefix){
         //1.生成时间戳
        LocalDateTime now = LocalDateTime.now();
        long nowSecond = now.toEpochSecond(ZoneOffset.UTC);
        long timestamp = nowSecond - BEGIN_TIMESTAMP;
        //2.生成序列号,  获取当天日期， 再去做自增长
        String date = now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        Long count = stringRedisTemplate.opsForValue().increment("icr:" + keyPrefix + ":" + date);
        //3.拼接返回

        return timestamp << COUNT_BITS | count ;

    }
}
